/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *         Simon Goldschmidt
 *
 */

/**
 * @file
 * Stack-internal timers implementation.
 * This file includes timer callbacks for stack-internal timers as well as
 * functions to set up or stop timers and check for expired timers.
 *
 */

#include <net/lwip/opt.h>

#include <net/lwip/timers.h>
#include <net/lwip/tcp_impl.h>

#if LWIP_TIMERS

#include <net/lwip/def.h>
#include <net/lwip/memp.h>
#include <net/lwip/tcpip.h>

#include <net/lwip/ipv4/ip_frag.h>
#include <net/lwip/netif/etharp.h>
#include <net/lwip/dhcp.h>
#include <net/lwip/ipv4/autoip.h>
#include <net/lwip/ipv4/igmp.h>
#include <net/lwip/sys.h>
#include <net/lwip/pbuf.h>

/** The one and only timeout list */
static struct sys_timeo *next_timeout;
#if NO_SYS
static systime_t timeouts_last_time;
#endif							/* NO_SYS */

#if LWIP_TCP
/** global variable that shows if the tcp timer is currently scheduled or not */
static int tcpip_tcp_timer_active;

/**
 * Timer callback function that calls tcp_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void tcpip_tcp_timer(void *arg)
{
	LWIP_UNUSED_ARG(arg);

	/* call TCP timer handler */
	tcp_tmr();
	/* timer still needed? */
	if (tcp_active_pcbs || tcp_tw_pcbs) {
		/* restart timer */
		sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
	} else {
		/* disable timer */
		tcpip_tcp_timer_active = 0;
	}
}

/**
 * Called from TCP_REG when registering a new PCB:
 * the reason is to have the TCP timer only running when
 * there are active (or time-wait) PCBs.
 */
void tcp_timer_needed(void)
{
	/* timer is off but needed again? */
	if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) {
		/* enable and start timer */
		tcpip_tcp_timer_active = 1;
		sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
	}
}
#endif							/* LWIP_TCP */

#if IP_REASSEMBLY
/**
 * Timer callback function that calls ip_reass_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void ip_reass_timer(void *arg)
{
	LWIP_UNUSED_ARG(arg);
	LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: ip_reass_tmr()\n"));
	ip_reass_tmr();
	sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
}
#endif							/* IP_REASSEMBLY */

#if LWIP_ARP
/**
 * Timer callback function that calls etharp_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void arp_timer(void *arg)
{
	LWIP_UNUSED_ARG(arg);
	LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: etharp_tmr()\n"));
	etharp_tmr();
	sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
}
#endif							/* LWIP_ARP */

#if LWIP_DHCP
/**
 * Timer callback function that calls dhcp_coarse_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void dhcp_timer_coarse(void *arg)
{
	LWIP_UNUSED_ARG(arg);
	LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dhcp_coarse_tmr()\n"));
	dhcp_coarse_tmr();
	sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
}

/**
 * Timer callback function that calls dhcp_fine_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void dhcp_timer_fine(void *arg)
{
	LWIP_UNUSED_ARG(arg);
	LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: dhcp_fine_tmr()\n"));
	dhcp_fine_tmr();
	sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
}
#endif							/* LWIP_DHCP */

#if LWIP_AUTOIP
/**
 * Timer callback function that calls autoip_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void autoip_timer(void *arg)
{
	LWIP_UNUSED_ARG(arg);
	LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: autoip_tmr()\n"));
	autoip_tmr();
	sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
}
#endif							/* LWIP_AUTOIP */

#if LWIP_IGMP
/**
 * Timer callback function that calls igmp_tmr() and reschedules itself.
 *
 * @param arg unused argument
 */
static void igmp_timer(void *arg)
{
	LWIP_UNUSED_ARG(arg);
	LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: igmp_tmr()\n"));
	igmp_tmr();
	sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
}
#endif							/* LWIP_IGMP */

/** Initialize this module */
void sys_timeouts_init(void)
{
#if IP_REASSEMBLY
	sys_timeout(IP_TMR_INTERVAL, ip_reass_timer, NULL);
#endif							/* IP_REASSEMBLY */
#if LWIP_ARP
	sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
#endif							/* LWIP_ARP */
#if LWIP_DHCP
	sys_timeout(DHCP_COARSE_TIMER_MSECS, dhcp_timer_coarse, NULL);
	sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
#endif							/* LWIP_DHCP */
#if LWIP_AUTOIP
	sys_timeout(AUTOIP_TMR_INTERVAL, autoip_timer, NULL);
#endif							/* LWIP_AUTOIP */
#if LWIP_IGMP
	sys_timeout(IGMP_TMR_INTERVAL, igmp_timer, NULL);
#endif							/* LWIP_IGMP */

#if NO_SYS
	/* Initialise timestamp for sys_check_timeouts */
	timeouts_last_time = sys_now();
#endif
}

/**
 * Create a one-shot timer (aka timeout). Timeouts are processed in the
 * following cases:
 * - while waiting for a message using sys_timeouts_mbox_fetch()
 * - by calling sys_check_timeouts() (NO_SYS==1 only)
 *
 * @param msecs time in milliseconds after that the timer should expire
 * @param handler callback function to call when msecs have elapsed
 * @param arg argument to pass to the callback function
 */
#if LWIP_DEBUG_TIMERNAMES
void sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char *handler_name)
#else							/* LWIP_DEBUG_TIMERNAMES */
void sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
#endif							/* LWIP_DEBUG_TIMERNAMES */
{
	struct sys_timeo *timeout, *t;

	timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
	if (timeout == NULL) {
		LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
		return;
	}
	timeout->next = NULL;
	timeout->h = handler;
	timeout->arg = arg;
	timeout->time = msecs;
#if LWIP_DEBUG_TIMERNAMES
	timeout->handler_name = handler_name;
	LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p msecs=%" U32_F " handler=%s arg=%p\n", (void *)timeout, msecs, handler_name, (void *)arg));
#endif							/* LWIP_DEBUG_TIMERNAMES */

	if (next_timeout == NULL) {
		next_timeout = timeout;
		return;
	}

	if (next_timeout->time > msecs) {
		next_timeout->time -= msecs;
		timeout->next = next_timeout;
		next_timeout = timeout;
	} else {
		for (t = next_timeout; t != NULL; t = t->next) {
			timeout->time -= t->time;
			if (t->next == NULL || t->next->time > timeout->time) {
				if (t->next != NULL) {
					t->next->time -= timeout->time;
				}
				timeout->next = t->next;
				t->next = timeout;
				break;
			}
		}
	}
}

/**
 * Go through timeout list (for this task only) and remove the first matching
 * entry, even though the timeout has not triggered yet.
 *
 * @note This function only works as expected if there is only one timeout
 * calling 'handler' in the list of timeouts.
 *
 * @param handler callback function that would be called by the timeout
 * @param arg callback argument that would be passed to handler
*/
void sys_untimeout(sys_timeout_handler handler, void *arg)
{
	struct sys_timeo *prev_t, *t;

	if (next_timeout == NULL) {
		return;
	}

	for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
		if ((t->h == handler) && (t->arg == arg)) {
			/* We have a match */
			/* Unlink from previous in list */
			if (prev_t == NULL) {
				next_timeout = t->next;
			} else {
				prev_t->next = t->next;
			}
			/* If not the last one, add time of this one back to next */
			if (t->next != NULL) {
				t->next->time += t->time;
			}
			memp_free(MEMP_SYS_TIMEOUT, t);
			return;
		}
	}
	return;
}

#if NO_SYS

/** Handle timeouts for NO_SYS==1 (i.e. without using
 * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
 * handler functions when timeouts expire.
 *
 * Must be called periodically from your main loop.
 */
void sys_check_timeouts(void)
{
	if (next_timeout) {
		struct sys_timeo *tmptimeout;
		u32_t diff;
		sys_timeout_handler handler;
		void *arg;
		u8_t had_one;
		systime_t now;

		now = sys_now();
		/* this cares for wraparounds */
		diff = now - timeouts_last_time;
		do {
#if PBUF_POOL_FREE_OOSEQ
			PBUF_CHECK_FREE_OOSEQ();
#endif							/* PBUF_POOL_FREE_OOSEQ */
			had_one = 0;
			tmptimeout = next_timeout;
			if (tmptimeout && (tmptimeout->time <= diff)) {
				/* timeout has expired */
				had_one = 1;
				timeouts_last_time = now;
				diff -= tmptimeout->time;
				next_timeout = tmptimeout->next;
				handler = tmptimeout->h;
				arg = tmptimeout->arg;
#if LWIP_DEBUG_TIMERNAMES
				if (handler != NULL) {
					LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s arg=%p\n", tmptimeout->handler_name, arg));
				}
#endif							/* LWIP_DEBUG_TIMERNAMES */
				memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
				if (handler != NULL) {
					handler(arg);
				}
			}
			/* repeat until all expired timers have been called */
		} while (had_one);
	}
}

/** Set back the timestamp of the last call to sys_check_timeouts()
 * This is necessary if sys_check_timeouts() hasn't been called for a long
 * time (e.g. while saving energy) to prevent all timer functions of that
 * period being called.
 */
void sys_restart_timeouts(void)
{
	timeouts_last_time = sys_now();
}

#else							/* NO_SYS */

/**
 * Wait (forever) for a message to arrive in an mbox.
 * While waiting, timeouts are processed.
 *
 * @param mbox the mbox to fetch the message from
 * @param msg the place to store the message
 */
void sys_timeouts_mbox_fetch(sys_mbox_t *mbox, void **msg)
{
	u32_t time_needed;
	struct sys_timeo *tmptimeout;
	sys_timeout_handler handler;
	void *arg;

again:
	if (!next_timeout) {
		LWIP_DEBUGF(TIMERS_DEBUG, ("next_timeout is null"));
		time_needed = sys_arch_mbox_fetch(mbox, msg, 0);
	} else {
		if (next_timeout->time > 0) {
			time_needed = sys_arch_mbox_fetch(mbox, msg, next_timeout->time);
		} else {
			time_needed = SYS_ARCH_TIMEOUT;
		}

		if (time_needed == SYS_ARCH_TIMEOUT) {
			/* If time == SYS_ARCH_TIMEOUT, a timeout occured before a message
			   could be fetched. We should now call the timeout handler and
			   deallocate the memory allocated for the timeout. */
			tmptimeout = next_timeout;
			next_timeout = tmptimeout->next;
			handler = tmptimeout->h;
			arg = tmptimeout->arg;
#if LWIP_DEBUG_TIMERNAMES
			if (handler != NULL) {
				LWIP_DEBUGF(TIMERS_DEBUG, ("stmf calling h=%s arg=%p\n", tmptimeout->handler_name, arg));
			}
#endif							/* LWIP_DEBUG_TIMERNAMES */
			memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
			if (handler != NULL) {
				/* For LWIP_TCPIP_CORE_LOCKING, lock the core before calling the
				   timeout handler function. */
				LOCK_TCPIP_CORE();
				handler(arg);
				UNLOCK_TCPIP_CORE();
			}
			LWIP_TCPIP_THREAD_ALIVE();

			/* We try again to fetch a message from the mbox. */
			goto again;
		} else {
			/* If time != SYS_ARCH_TIMEOUT, a message was received before the timeout
			   occured. The time variable is set to the number of
			   milliseconds we waited for the message. */
			if (time_needed < next_timeout->time) {
				next_timeout->time -= time_needed;
			} else {
				next_timeout->time = 0;
			}
		}
	}
}

#endif							/* NO_SYS */

#else							/* LWIP_TIMERS */
/* Satisfy the TCP code which calls this function */
void tcp_timer_needed(void)
{
}
#endif							/* LWIP_TIMERS */
